Trigger the previous item in the active playlist
AI agents invoke audio_trigger_active_previous to trigger actions in Propresenter. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.
This tool executes an action (triggering previous track) in an external system (ProPresenter media player) whose effects depend on the runtime state of the playlist and audio system. It is not a simple read operation (doesn't just query state), nor does it create/modify persistent data. It has observable side effects on audio playback state, classifying it as Execute rather than Write.
From the tool's definition Tool name includes 'trigger' and description states 'Trigger the previous item in the active playlist', indicating it executes a command to control audio playback in ProPresenter 7.
Documented attack patterns abuse exactly the kind of access audio_trigger_active_previous gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Propresenter, and nothing reaches the server without passing your rules. This is the rule we recommend for audio_trigger_active_previous:
{
"version": "1",
"default": "deny",
"tools": {
"audio_trigger_active_previous": {
"limits": [
{
"counter": "audio_trigger_active_previous_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}audio_trigger_active_previous stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.
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Trigger the previous item in the active playlist. It is categorised as a Execute tool in the Propresenter MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Propresenter MCP server in PolicyLayer and add a rule for audio_trigger_active_previous: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Propresenter. Nothing to install.
audio_trigger_active_previous is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the audio_trigger_active_previous rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for audio_trigger_active_previous. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
audio_trigger_active_previous is provided by the Propresenter MCP server (@alxpark/propresenter-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Propresenter, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
177 Propresenter tools catalogued and risk-classified — across an index of 43,000+ MCP servers.